ABSTRACT Support is requested for a Keystone Symposia conference entitled Stromal Cells in Immunity and Disease, organized by Drs. Scott N. Mueller, Jason G. Cyster, Reina E. Mebius and Theresa Lu. The conference will be held in Victoria, British Columbia Canada from February 19-23, 2020. Non-hematopoietic stromal cells play important roles in many tissues, constructing tissue microenvironments, contributing to tissue repair, defense and immune responses. Within lymphoid organs, stromal cells organize and interact with leukocytes in an immunologically important manner. In addition to organizing T and B cell segregation and expressing lymphocyte survival factors, stromal cells support the migration and interactions between antigen presenting cells and nave T and B cells during the initiation of immune responses and influence the outcome between tolerance and immunity. Stromal cells also play instrumental roles in coordinating immune responses in non-lymphoid tissues and in inflammatory and autoimmune diseases, and in chronic infection. For instance, stromal cells have been shown to be dysregulated during HIV infection and also in cancer patients. Furthermore, stromal cells are being harnessed for therapeutic applications in several diseases, an area that holds great promise for improving human health. Our understanding of stromal cell populations and their contributions to innate and adaptive immunity as well as immunological diseases, cancer and vaccination has grown exponentially over the past few years. This emerging field has gained enormous momentum due to increasingly sophisticated tools to dissect the fundamental biology and clinical importance of this cellular compartment. This conference is being held jointly with Fibrosis and Tissue Repair: From Molecules and Mechanics to Therapeutic Approaches. This joint pairing will bring together basic and clinical scientists with interdisciplinary interests in stromal cell biology and disease treatment to discuss critical fundamental and translational advances. The goals of this conference are to showcase cutting-edge results and new directions in the field, stimulate interactions and provide a forum for trainees and new investigators to present their work and interact with leaders in the field.